Apparatus for straightening, untwisting and testing tubular elements

ABSTRACT

An improved apparatus for straightening, untwisting, testing and strengthening sucker rods and tubular elements such as oil well drill pipe, tubing and the like, comprising an extendable frame having opposite ends with a rotary supporting head mounted on each end thereof and adapted to support the respective opposite ends of a tubular element to be straightened. Extendable power cylinders are provided for moving the rotary supporting heads apart thereby stretching, straightening, untwisting and testing deformed sucker rods and tubular elements.

United States Patent Heldenbrand 1 Nov. 6, 1973 [54] APPARATUS FOR STRAIGHTENING, 2,487,972 11 /1949 Katz 72/299 UNTWISTING AND TESTlNG TUBULAR 2,352,442 6/1944 Loewy et al. 72/299 ELEMENTS Everett A. Heldenbrand, Odessa, Tex.

Inventor:

Assignee: Heldies Portable Pipe Service, Inc.,

Odessa, Tex.

Filed: Mar. 9, 1972 Appl. No.: 233,204

US. Cl 72/302, 72/299, 72/310 Int. Cl B2ld 11/02 Field of Search 72/293, 296, 299,

References Cited UNITED STATES PATENTS 5/1959 Heldenbrand 72/302 7/1939 Nighthart 72/302 Primary Examiner-Charles W. Lanham Assistant Examiner-M. J. Keenan Attorney-Jerry J. Dunlap et a1.

[57] ABSTRACT An improved apparatus for straightening, untwisting, testing and strengthening sucker rods and tubular elements such as oil well drill pipe, tubing and the like, comprising an extendable frame having opposite ends with a rotary supporting head mounted on each end thereof and adapted to support the respective opposite ends of a tubular element to be straightened. Extendable power cylinders are provided for moving the rotary supporting heads apart 1 thereby stretching, straightening, untwisting and testing deformed sucker rods and tubular elements.

9 Claims, 4 Drawing Figures APPARATUS FOR STRAIGHTENING, UNTWISTING AND TESTING TUBULAR ELEMENTS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to improvements in apparatus for strengthening sucker rodsand tubular elements, and more particularly, but not by way of limitation, to improved apparatus for straightening, untwisting, testing and strengthening oil well drill pipe, oil well tubing, sucker rods and the like.

2. Description of the Prior Art As is well known in the oil industry, drill pipe, sucker rods and well tubing frequently become bent, both through transportation and use. An early practice in the industry was to straighten such elements by holding the elements and applying a force transverse to the crooked or bent portion of the element. In straightening an element by this method, the element was fre quently weakened at the various points along its length and was rendered potentially dangerous for furture use. Furthermore, the threads at each end of the pipe or tubing were frequently deformed slightly out of alignment with the longitudinal axis of the pipe. When such pipe was straightened by the early methods, the threads were not aligned with the remainder of the pipe. Therefore, when another joint of drill pipe or tubing was attached thereto, the adjacent joints were not in alignment. In addition, no provision was made for testing the strength of the straightened drill pipe or tubing, nor the alignment of the threads. As a result, the operating condition of the straightened pipe or tubing was not discovered until it had been run into an oil well and actually placed in operation.

In the patent entitled METHOD OF STRAIGHT- ENING AND TESTING TUBULAR ELEMENTS," US. Pat. No. 2,884,986, and issued on May 5, 1959, there is disclosed therein apparatus for straightening and testing tubular elements wherein the pipe or tubing is, in effect, stressed to approximately its minimum tensile strength. The stressing or pulling is accomplished by grasping the opposite ends of the element through the medium of its threads. Therefore, when the element is placed in tension, the threads will be aligned. with the longitudinal axis of the element simultaneously with the. straightening operation. Furthermore, the threads will strength in the threaded portions, such as drill pipe,

upset tubing and the like, and for sucker rods..

The prior art methods and apparatus for straightening tubular elements are primarily directed toward straightening tubular elements which are bent and deformed out of alignment with the intended longitudinal axis. However, many times tubular elements suchas oil well drill pipe are twisted about the longitudinal axis due to breakage of the drill pipe string during thedrilling operation. The known prior art pipe straightening apparatus ordinarily have no satisfactory provision made for untwisting such twisted tubular members.

SUMMARY OF THE INVENTION The present invention contemplates an apparatus for straightening, untwisting and testing crooked and twisted pipe or rod which apparatus includes a frame having opposite ends; a pair of extendable power cylinders each having a cylinder end and a rod end and carried by saidframe with the cylinder end rigidly secured thereto; a first retaining plate fixedly secured to one end of said frame; a second retaining plate fixedly secured to the rod ends of said extendable power cylinders proximate to the opposite end of said frame; and

a pair of apertures formed respectively in said first and second retaining plates and positioned in axial align ment with one another-and in substantially parallel alignment with said extendable power cylinders. This apparatus includes theimprovement comprising first support means rotatably carried by one of said retaining plates substantially coaxial with said aperture formed therein for engaging one end of said crooked and twisted pipe or rod; and second support means carried by the other of said retaining plates substantially coaxial with said aperture formed therein for engaging the opposite end of said crooked and twisted pipe or rod.

An object of the present invention is to provide an apparatus for straightening, untwisting and testing crooked and twisted pipe or rod having increased efficiency.

Another object of the present invention is to provide an apparatus for straightening, untwisting and testing crooked and twisted pipe or rod which allows the pipe to rotate relative to the apparatus during the straightening and untwisting operation.

A further object of the present invention is to provide an apparatus for straightening, untwisting and testing crooked and twisted pipe or rod which is economical in construction and operation.

Other objects and advantages of the present invention willbe evident from the following detailed description when read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially schematic plan view of the apparatus of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

FIG. Sis an enlarged cross-sectional view taken along line 3--3 of FIG. 1.

FIG. 4 is an enlarged cross-sectional view taken along line 44 of FIG. 1.

DESCRIPTIONOF THE PREFERRED EMBODIMENT Referring to the drawings in detail, and particularly FIGS. land 2, reference character 10 generally designates a straightening, untwisting and testing machine comprising a pairof parallel and horizontally disposed support members 12 and 14, preferably formed from angle iron as illustrated. A plurality of support legs 16 are rigidly attached to the members 12 and 14 to support the machine 10 at the desired height. A plurality of braces 18 (only one of which is shown) are secured to the members 12 and 14 in spaced relation along the length of the machine to retain the support members in the desired parallel relationship. A transverse retaining plate is rigidly secured to the ends 22 and 24 of the members 12 and 14 for purposes to be hereinafter set forth.

Two hydraulic cylinders 26 are rigidly secured respectively to each of the support members 12 and 14 in parallel relationship. Each cylinder 26 is provided with a plunger 28 (see FIG. 2) reciprocably disposed therein, and each plunger 28 has a plunger or piston rod 30 which extends outwardly from the end of the respective cylinder 26 in a direction away from the retaining plate 20. Another retaining plate 32 is rigidly secured to the outer ends of the plunger rods 30 for purposes which will be hereinafter set forth.

A hydraulic pump and control unit, schematically illustrated at 34, is supported on the support member 12 to supply fluid under pressure through a conduit 36 to the ends of the cylinders 26 opposite the plunger rods 30. The pump unit 34 (and associated mechanism) is preferably of a type adapted to supply hydraulic fluid under pressure to the cylinders 26 until the resistance to pressure is slightly reduced. Such a pump unit is disclosed in the application of A.P. Heldenbrand entitled Automatic Hydraulic Pressure Release Device, filed Feb. 1, 1954, Ser. No. 407,481, now US. Pat. No. 2,849,021. Springs 38 are interconnected between support members 12 and 14 and the retaining plate 32 to constantly urge the plungers 28 and the rods 30 inwardly into the cylinders 26.

Apertures 40 and 42 are formed respectively in retaining plates 20 and 32 and are in axial alignment with one another and parallel alignment with the longitudinal axes of the hydraulic cylinders 26. A cylindrically shaped hub carrier 44 is fixedly secured to the retaining plate 20, by suitable means such as welding; with the cylindrically shaped inner periphery 46 thereof axially aligned with the aperture 40 formed in the retaining plate 20. A cylindrically shaped hub carrier 48 is fixedly secured to the retaining plate 32, by suitable means such as welding, with the cylindrically shaped inner periphery 50 thereof in axial alignment withthe aperture 42 formed in the retaining plate 32. It is readily apparent that this positioning of the hub carriers 44 and 48 places their respective inner peripheries 46 and 50 in coaxial alignment.

Rotary head assemblies 52 and 54 are rotatably mounted on the retaining plates 20 and 32 respectively. The rotary head assemblies 52 and 54 are identical in construction, each comprising a hub member 56, a thrust bearing 58, a bearing retaining collar 60 for securing the thrust bearing 58 to the hub member 56, and a retaining nut 62 for retaining the rotary head assemblies 52 and 54 to the respective retaining plates 20 and 32.

The hub member 56 has a first end portion 64, a second end portion 66 and a bore 68 extending therethrough and intersecting the first and second end portions. The outer periphery 70 of the hub member 56 is cylindrically shaped with the portion thereof adjacent to the first end portion 64 threaded to receive the retaining nut 62. A circumferential flange 72 extends outwardly from the outer periphery 70 adjacent to the second end portion 66 of the hub member 56.

The bearing retaining collar 60 is disposed about the outer periphery 74 of the flange 72 and is secured thereto preferably by a plurality of set screws 76 disposed about the collar in spaced relation. The bearing retaining collar 60 has an L-shaped cross section which is characterized by an inwardly extending annular flange portion 78.

The thrust bearing 58 is disposed within the bearing retaining collar 60 between the hub member 56 and the inwardly extending flange 78. The thrust bearing 58 comprises an interior bearing race 80, an exterior bearing race 82, and a plurality of bearing balls 84 disposed therebetween in spaced relation. The bearing balls 84 are disposed therebetween in spaced relation. The

bearing balls 84 are disposed in annular grooves 86 and' 88 formed respectively in the bearing races and 82. The bearing races 80 and 82 are sized to permit the free rotation of bearing race 82 relative to bearing race 80 within the bearing retaining collar 60. Bores 90 and 92 are formed respectively in the bearing races 80 and 82 and are axially aligned with each other and with the bore 68 formed in the hub member 56. The bores 90, 92 and 68 are substantially equal in diameter which diameter is of sufficient size to allow the passage of the end of a dril pipe therethrough for purposes which will be explained more fully hereinafter.

When properly installed, the first end portion 64'of the hub member 56 of the rotary head assembly 52 extends through the inner periphery 46 of the hub carrier 44 and through the aperture 40 of the retaining plate 20. The rotary head assembly 52 is retained in this position by means of the retaining nut 62 which is threadedly secured to the first end portion 64 of the hub member 56. A plurality of bearing rollers 94 are disposed between the outer periphery 70 of the hub member 56 and the inner periphery 46 of the hub carrier 44 to rotatably support the rotary head assembly 52 on the retaining plate 20. It should be noted that other forms of rotary bearings may be substituted for the bearing rollers 94 such as needle bearings or ball bearings of conventional design well known in the art.

Similarly, the rotary head assembly 54 is properly mounted on the retaining plate 32 by extending the first end portion 64 of the hub member 56 of the rotary head assembly 54 through the inner periphery 50 of the hub carrier 48 and the aperture 42 of the retaining plate 32. The rotary head assembly 54 is retained in assembled position by means of the retaining nut 62 which is threadedly secured to the first end portion 64 of the hub member 56. A plurality of bearing rollers 94 are disposed between the outer periphery 70 of the hub member 56 of the rotary head assembly 54 and the inner periphery 50 of the hub carrier 48 to rotatably support the rotary head assembly 54 on the retaining plate 32. As noted above, conventional needle or ball bearings may be substituted for the bearing rollers 94.

The crooked or twisted drill pipe, sucker rod or the like 96 is secured to the retaining plates 20 and 32 by means of threaded pull pins 98 and 100, respectively. As shown in FIG. 3, the pull pin 98 comprises a cylindrical body member 102 of a size to extend through the bores 92, 90 and 68 of the rotary head assembly 52. The inner end 104 of the body 102 is counterbored and threaded at 106 to receive the niale threaded end 108 of the drill pipe 96. A circumferential flange 110 extends outwardly from the medial portion of the body 102 to abut the exterior bearing race 82 of the rotary assembly 52 around the bore 92.

As shown in FIG. 4, the pull pin is also provided with a cylindrical body portion 112 of a size to extend through the bores 92, 90 and 68 of the rotary head assembly 54. The inner end 114 of the body 112 is reduced in diameter and threaded to receive the female threaded end 116 of the drill pipe 96. A circumferential flange 118 is also provided around the medial portion of the pin 100 to abut the exterior bearing race 82 of the rotary head assembly 54 around the bore 92.

In constructing the apparatus 10, the retaining plates and 32 are secured at right angles to the longitudinal axes of the cylinders 26, and, as previously noted, the bores 68, 90 and 92 of the respective rotary head assemblies 52 and 54 are positioned in axial alignment with one another. Furthermore, the inner faces of the pull pin flanges 110 and 118, and the mating exterior bearing races 82 of the rotary head assemblies 52 and 54 are preferably machined to provide a close fit and position the pull pins 98 and 100 in axial alignment.

Suitable gusset braces 120 are preferably secured between the hub carriers 44 and 48 and the respective retaining plates 20 and 32 to prevent bending of the retaining plates 20 and 32 when operating the apparatus 10.

OPERATION OF THE PREFERRED EMBODIMENTS In operation of the apparatus 10, the crooked drill pipe, sucker rod or the like 96 is placed between the support members 12 and 14, as illustrated in FIG. 1, and is then secured to the pull pins 98 and 100. The pull pins 98 and 100 are threaded tightly on the respective ends 108 and 116 of the drill pipes 96. The pumping unit 34 is then placed in operation to supply fluid into the cylinders 26 and expand or expel the plunger rods 30 outwardly from the cylinders 26 in a uniform manner. It will be observed that the pressure conduit 36 will supply an equal amount of fluid to each of the cylinders 26 to move the piston rods 30 an equal distance and with an equal force.

As the piston rods 30 and the retaining plate 32 are moved in a direction away from the retaining plate 20, the pull of the pin flanges 110 and 118 will contact the exterior bearing races 82 of the rotary head assemblies 52 and 54 respectively, and the drill pipe 96 will be placed under tension. The resulting tension will stress align the entire length of the drill pipe 96. Simultaneously, the threaded engagement of the pull pins 98 and 100 with the opposite ends 108 and 116 of the drill pipe 96 will test the shear strength of the drill pipe threads and align the threads with the longitudinal axis of the drill pipe. Further, the resulting tension will cause twisted drill pipe 96 to untwist. This untwisting action is facilitated by the thrust bearings 58 of the rotary head assemblies 52 and 54 which virtually eliminate any apparatus-induced resistance to the untwisting and straightening of the drill pipe 96.

When a sufficient force is applied to bring the drill pipe 96 to its yield point, the plungers 28 will begin to move in the cylinders 26 at a faster rate. Whereupon, the pumping unit 34 will cease to operate and will release the hydraulic pressure in the cylinders 26. In placing the drill pipe 96 under tension to its yield point, or Slightly beyond its minimum yield point, the pipe 96 is adequately tested for tensile strength. If the pipe 96 has the desired tensile strength, it becomes stress-aligned to provide increased and uniform strength throughout the entire length thereof. If the pipe 96 is below a specified tensile strength, the pipe will be slightly stretched to actuate the unit 34 and release the hydraulic pressure in the cylinders 26 at a pressure (as indicated by the unit 23) below the pressure required to apply the calculated minimum stress, or-in some instances the pipe will be parted.

When the drill pipe 96 has been straightened, the pull pins 98 and are unthreaded and the pipe 96 removed from the apparatus 10, whereupon the springs 388 will retract the plunger rods 30 into the dylinders 26 and the machine will be ready for a subsequent straightening operation.

From the foregoing, it is apparent that the present invention provides a novel method of straightening, untwisting and testing drill pipe sucker rods and the like, wherein the drill pipe is placed under tension through the medium of the threads at each end thereof. The threads of the drill pipe, sucker rods or the like are aligned with the longitudinal axis of the drill pipe or sucker rod simultaneously with the straightening and untwisting operation, and the entire lengthof the drill pipe or sucker rod joint is stress aligned to assure uniform strength throughout. The apparatus of the present invention is economical to construct and simple to operate.

Changes may be made in the combination and arrangement of parts or elements as heretofore set forth in the specification and shown in the drawing, without departing from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. In an apparatus for straightening, untwisting, and testing a crooked and twisted length of pipe or rod which apparatus includes a frame having opposite ends; a pair of extendable power cylinders each having a cylinder end and a rod end and being carried by said frame with the cylinder ends rigidly secured thereto; a first retaining plate fixedly secured to one end of said frame; a second retaining plate fixedly secured to the rod ends of said extendable power cylinders proximate to the opposite end of said frame; and a pair of apertures formed respectively in said first and second. retaining plates and positioned in axial alignment with one another and in substantially parallel alignment with said extendable power cylinders, the improvement comprising:

first support head means freely rotatably carried by one of said retaining plates substantially coaxial with said aperture formed therein for engaging one end of said pipe or rod and freely rotating therewith; and

second support head means carried by the other of said retaining plates substantially coaxial with said aperture formed therein for engaging the opposite end of said pipe or rod.

2. The apparatus as defined in claim 1 wherein said first support head means is freely rotatably carriedby said second retaining plate and said second support head means is carried by said first retaining plate.

3. The apparatus as defined in claim 2 wherein said first support head means is further characterized to include:

a cylindrically shaped first hub carrier having a bore therethrough and fixedly secured to said second retaining plate coaxial with said aperture therethrough;

a first hub member having a bore therethrough and journaled in the bore through said first hub carrier;

a first thrust bearing having a bore therethrough carried by said first hub member; and

first pull pin means having an outwardly extending flange formed thereon for engaging said first thrust bearing and having pipe engaging means extending through the bore through said first thrust bearing for engaging one end of said pipe or rod.

4. The apparatus as defined in claim 3 wherein said second support head means is freely rotatably carried by said first retaining plate for freely rotating with the opposite end of said pipe or rod engaged thereby.

5. The apparatus as defined in claim 4 where said sec ond support head means is further characterized to include:

a cylindrically shaped second hub carrier having a bore therethrough and fixedly secured to said first retaining plate coaxial with said aperture therethrough; 1

a second hub member having a bore therethrough and journaled in the bore through said second hub carrier;

a second thrust bearing having a bore therethrough carried by said second hub member; and

second pull pin means having an outwardly extending flange formed thereon and engaging said second thrust bearing and having pipe engaging means extending through the bore through said thrust bearing for engaging the opposite end of said pipe or rod.

6. The apparatus as defined in claim 5 wherein said first thrust bearing comprises:

a first bearing race disposed adjacent to said first hub member and having an annular groove formed therein;

a second bearing race disposed proximate to said first bearing race and having an annular groove formed therein; and i a plurality of bearing balls disposed between said first and second bearing races and in the annular grooves formed therein; and

wherein said second thrust bearing comprises:

a first bearing race disposed adjacent to said second hub member and having an annular groove formed therein;

a second bearing race disposed proximate to said first bearing race and having an annular groove formed therein; and

a plurality of bearing balls disposed between said first and second bearing races and in the annular grooves formed therein.

7. The apparatus as defined in claim 6 further characterized to include:

first retaining means secured to said first hub member for retaining said first hub member in the bore through said first hub carrier; and

second retaining means secured to said second hub member for retaining said second hub member in the bore through said second hub carrier.

8. The apparatus as defined in claim 7 further characterized to include:

first bearing means disposed in the bore through said first hub carrier for rotatably supporting said first hub member journaled therein; and

second bearing means disposed in the bore through said second hub carrier for rotatably supporting said second hub member journaled therein.

9. The apparatus as defined in claim 8 wherein said first and second bearing means are each further characterized to include a plurality of bearing rollers.

*zgz gg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 7m 836 Dated November 6. 1973 Inventofls) Enema; g H Jd br rirI It is certified that error appears in the above-identified patent and that said Letters Patent are hereby correeted as shown below:

r I I Incolumn 3, line 36, "we1ding;" should be --we1ding,-.

In column 4, lines 10 and 11, after "relation." delete ,"The bearing balls 84 are disposed therebetween in spaced relation."

In column 4, line 22, "dril should be --dri11.

In column 6, line 9, 388" shou1d be --3 s--.

Signed and sealed this 19th day of March 197 4 (SEAL) Attest:

EDWARD M.FLET( JHER,JR. C. MARSHALL DANN Attestlng Offlcer Commissioner of Patents 

1. In an apparatus for straightening, untwisting, and testing a crooked and twisted length of pipe or rod which apparatus includes a frame having opposite ends; a pair of extendable power cylinders each having a cylinder end and a rod end and being carried by said frame with the cylinder ends rigidly secured thereto; a first retaining plate fixedly secured to one end of said frame; a second retaining plate fixedly secured to the rod ends of said extendable power cylinders proximate to the opposite end of said frame; and a pair of apertureS formed respectively in said first and second retaining plates and positioned in axial alignment with one another and in substantially parallel alignment with said extendable power cylinders, the improvement comprising: first support head means freely rotatably carried by one of said retaining plates substantially coaxial with said aperture formed therein for engaging one end of said pipe or rod and freely rotating therewith; and second support head means carried by the other of said retaining plates substantially coaxial with said aperture formed therein for engaging the opposite end of said pipe or rod.
 2. The apparatus as defined in claim 1 wherein said first support head means is freely rotatably carried by said second retaining plate and said second support head means is carried by said first retaining plate.
 3. The apparatus as defined in claim 2 wherein said first support head means is further characterized to include: a cylindrically shaped first hub carrier having a bore therethrough and fixedly secured to said second retaining plate coaxial with said aperture therethrough; a first hub member having a bore therethrough and journaled in the bore through said first hub carrier; a first thrust bearing having a bore therethrough carried by said first hub member; and first pull pin means having an outwardly extending flange formed thereon for engaging said first thrust bearing and having pipe engaging means extending through the bore through said first thrust bearing for engaging one end of said pipe or rod.
 4. The apparatus as defined in claim 3 wherein said second support head means is freely rotatably carried by said first retaining plate for freely rotating with the opposite end of said pipe or rod engaged thereby.
 5. The apparatus as defined in claim 4 where said second support head means is further characterized to include: a cylindrically shaped second hub carrier having a bore therethrough and fixedly secured to said first retaining plate coaxial with said aperture therethrough; a second hub member having a bore therethrough and journaled in the bore through said second hub carrier; a second thrust bearing having a bore therethrough carried by said second hub member; and second pull pin means having an outwardly extending flange formed thereon and engaging said second thrust bearing and having pipe engaging means extending through the bore through said thrust bearing for engaging the opposite end of said pipe or rod.
 6. The apparatus as defined in claim 5 wherein said first thrust bearing comprises: a first bearing race disposed adjacent to said first hub member and having an annular groove formed therein; a second bearing race disposed proximate to said first bearing race and having an annular groove formed therein; and a plurality of bearing balls disposed between said first and second bearing races and in the annular grooves formed therein; and wherein said second thrust bearing comprises: a first bearing race disposed adjacent to said second hub member and having an annular groove formed therein; a second bearing race disposed proximate to said first bearing race and having an annular groove formed therein; and a plurality of bearing balls disposed between said first and second bearing races and in the annular grooves formed therein.
 7. The apparatus as defined in claim 6 further characterized to include: first retaining means secured to said first hub member for retaining said first hub member in the bore through said first hub carrier; and second retaining means secured to said second hub member for retaining said second hub member in the bore through said second hub carrier.
 8. The apparatus as defined in claim 7 further characterized to include: first bearing means disposed in the bore through said first hub carrier for rotatably supporting said first hub member journaled therein; and second bearing means disposed in the boRe through said second hub carrier for rotatably supporting said second hub member journaled therein.
 9. The apparatus as defined in claim 8 wherein said first and second bearing means are each further characterized to include a plurality of bearing rollers. 